Petrus worked out for the team on Monday, and could provide depth along the interior of the offensive line, where the Patriots are dealing with injuries to both of their starting guards, Dan Connolly and Logan Mankins. Both players left Sunday's game, although the extent of their injuries remains unclear.
Originally a 2010 sixth-round pick of the Giants, Petrus has started three games in his career and played in 17 total. The Arkansas product was waived on Nov. 3.
Harris, an undrafted free agent out of Alabama in 2012, was signed to the practice squad on Nov. 6.
Also, the Patriots worked out a pair of linebackers on Tuesday, according to a source: Mister Alexander and Dom DeCicco. Alexander was released by the Texans on Oct. 31, while DeCicco was last with the Bears, who released him on Aug. 29.